Tennis ball felt and tennis ball

ABSTRACT

To provide a tennis ball felt which has less occurrence of creases at the time of forming a tennis ball. According to one embodiment, a tennis bass felt, which is covered on a core of a tennis ball, includes: a base fabric formed of stretchy material; and fibers fixed with the base fabric.

BACKGROUND

1. Field of the Invention

The present invention relates to a felt used for an outer surface(melton) of a tennis ball and a tennis ball using the felt, and moreparticularly to a tennis ball felt which has less occurrence of creasesat the time of forming a tennis ball and a tennis ball using the felt.

2. Description of the Related Art

As a tennis ball, as shown in FIG. 3, there is used what includes a core10 and a felt 12 covered on the core. Usually, the core is formed ofrubber in a spherical shape, and the felt is substantially gourd-shaped.Two sheets of felt are adhered to the core with a rubber adhesive. InFIG. 3, reference numeral 14 represents a joint between two sheets offelt where the above rubber adhesive is exposed.

As the above-mentioned tennis ball felt, a woven felt or a needle feltis used (refer to JP-A-2003-154037). The woven felt, in which a surfaceof a woven fabric is fluffed up, is made by subjecting a raw fabric toraising-processing and milling-processing. The needle felt is, as shownin FIG. 4, made by implanting and fixing short fibers (batt fibers) 18onto a base fabric 16 by a needle-punch method (refer toJP-A-2007-308822).

The tennis ball using the woven felt for the outer surface (hereinafter,referred to as a “woven felt ball”) is more excellent in performancethan the tennis ball using the needle felt for the outer surface(hereinafter, referred to as a “needle felt ball”). However, the wovenfelt ball, since the felt is prone to fluff up and become worn, ismainly used for game. On the other hand, though the needle felt ball isinferior in performance to the woven belt ball, since the felt of theneedle felt ball is hard to fluff up and become worn and the needle feltball is inexpensive, the needle felt ball is mainly used for practice.

As types of tennis court, there are an en-tout-cas court made fromlateritious clay, an omni court made from sand-filled artificial turf, aclay court made from clay, a hard court made from concrete subjected torubber processing, a carpet court (for indoor) made from carpet-likematerial, and a grass court made from natural grass.

Of the aforementioned courts, there is a court where the felt of thetennis ball is prone to fluff up and therefore a ball using a felt whichis high in durability is preferably used. Its court is, for example, thecarpet court. Accordingly, in such the court, the aforementioned needlefelt ball is preferably used. However, in case that the needle felt ballis formed, there is a problem that creases are prone to occurparticularly in a circumferential edge portion (in the vicinity ofjoint) of the felt.

SUMMARY

An object of the invention is to provide a tennis ball felt which hasless occurrence of creases at the time of forming a tennis ball, and atennis ball using the felt.

Upon investigation of a cause of the aforementioned crease occurrence,the inventors have found out that since the conventional tennis ballneedle felt uses, as a base fabric, a woven fabric which uses a cottonfiber having no stretch property for one of the warp and the woof, and apolyester fiber having no stretch property for the other thereof, thebase fabric and the needle felt have the stretch property in neither ofthe longitudinal direction and the lateral direction, so that it isconceivable that when the felt is adhered to the core having thespherical body, creases are produced on the felt due to lack of thestretch property; and therefore, by providing the stretch property forthe base fabric thereby to provide the stretch property for the needlefelt, it is possible to prevent the creases from being produced on thefelt in the forming time of the needle felt ball.

The invention has been made on the basis of the above findings, and anobject of the invention is to provide a tennis ball felt of thefollowings.

According to a first aspect of the invention, there is provided a tennisbass felt, which is covered on a core of a tennis ball, including: abase fabric formed of stretchy material; and fibers fixed with the basefabric.

According to a second aspect of the invention, there is provided atennis bass felt, which is covered on a core of a tennis ball,including: a base fabric having a mesh structure which develops stretchproperty; and fibers fixed with the base fabric.

According to a third aspect of the invention, there is provided a tennisbass felt, which is covered on a core of a tennis ball, including: abase fabric formed of stretchy material and having a mesh structurewhich develops stretch property; and fibers fixed with the base fabric.

Further, according to a fourth aspect of the invention, there isprovided a tennis ball including a core and felt covered on the core, inwhich the felt is any of the first to third aspects.

Since the tennis ball felt of the invention has the aforementionedconstitution of the first to third aspects, it is conceivable that thefelt has the stretch property and therefore has less occurrence ofcreases at the time of forming the tennis ball.

According to the tennis ball felt and the tennis ball of the invention,creases are hard to be produced on the felt at the forming of the tennisball. Namely, according to the invention, it is possible to obtain atennis ball which is excellent in aesthetic appearance, and preventeffectively the irregular ball bound resulted from the creases producedon the felt.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingwhich is given by way of illustration only, and thus is not limitativeof the present invention and wherein:

FIGS. 1A and 1B are schematic diagrams each showing an example of themesh structure of a base fabric;

FIG. 2 is a graph showing a result of a test using a Tensilon tester inan embodiment;

FIG. 3 is a partially sectional front view showing an example of atennis ball; and

FIG. 4 is an explanatory view showing a needle felt.

DETAILED DESCRIPTION OF THE INVENTION

The invention will be described below more detailedly. A tennis ballfelt of the invention is formed by fixing a base fabric and fiberstogether. In the invention, in case that the base fabric is formed ofstretchy material, examples of the stretchy material can includestretchy polyurethane, polyethylene terephthalate, nylon, a mixture ofpolyurethane and polyethylene terephthalate, a mixture of polyurethaneand nylon, a mixture of nylon and polyethylene terephthalate, a mixtureof polyurethane, nylon and cotton, and synthetic rubber. The mostpreferable material of these materials is, from points of excellentstretch property, and suitable thickness and weight, polyurethane.

Further, in case that the base fabric having the mesh structure whichdevelops the stretch property is used, examples of the above meshstructure can include the structure shown in FIGS. 1A and 1B. In a meshstructure 20 shown in FIG. 1A, each mesh 22 is hexagonal; and in a meshstructure 30 shown in FIG. 1B, each mesh 32 is rhomboidal. The basefabric having the mesh structure of FIG. 1A or 1B has the stretchproperty in both of a longitudinal direction X and a lateral directionY. Therefore, the felt using the above base fabric has the stretchproperty in both of the longitudinal direction X and the lateraldirection Y. Examples of the mesh structure which develops the stretchproperty can include, in addition, the structure in which each mesh hasthe shape of an even-gon such as an octagon, and the structure in whicheach mesh is circular.

In case that the base fabric having the mesh structure which developsthe stretch property is used, the base fabric may be formed of materialhaving no stretch property. Examples of such the material having nostretch property can include non-stretch cotton and linen.

Though material of the fibers fixed to the base fabric is not limited,examples of the material can include a single material or a two or moresorts-mixture selected from a wool fiber, a nylon fiber, a polyesterfiber, an acrylic fiber, and a rayon fiber.

The tennis ball felt of the invention may have the stretch property inone or two directions of the longitudinal direction, the lateraldirection, and an oblique direction, or in all the directions. From apoint that the occurrence of creases on the felt is effectivelyprevented at the forming time of the tennis ball, it is preferable thatthe felt has the stretch property in all the directions. However, incase that the stretch property is provided for the felt by the basefabric having the mesh structure which develops the stretch property,since there is a direction where the felt cannot stretch depending onthe pulling direction, it is preferable that the felt is punched out soas to stretch at least in the longitudinal direction of thesubstantially gourd-shape.

In the invention, the fiber forming the felt is processed with a fibersoftening agent and subjected to soft finishing, whereby softeningproperty is provided for the fiber of the felt, and the occurrence ofthe creases on the felt can be prevented more at the forming time of thetennis ball. The fiber softening agent, which gives the softeningproperty to the fiber, is selected appropriately in response to materialof the fiber.

As a main component of the fiber softening agent, there are, forexample, cationic surfactants such as a polyamide type cationicsurfactant, a quarternary-ammonium salt type cationic surfactant, and anon-ion cationic surfactant; anionic surfactants such as an ester typenon-ion/anionic surfactant, a non-ion anionic surfactant, a higheralcohol-based anionic surfactant, a wax/non-ion/anionic surfactant, awax/non-ion/weak anionic surfactant; nonionic surfactants such as apolyhydric alcohol-based nonionic surfactant, a polyhydric alcohol estertype nonionic surfactant, a polyether type nonionic surfactant, awax/nonionic surfactant, and a wax/weak cation/nonionic surfactant; asilicon oil; and a modified silicon oil.

A particularly preferable main component of the fiber softening agent isthe polyamide type cationic surfactant. By using this surfactant, it ispossible to obtain effects that resilient and soft textures can be addedto the fiber and a fiber which is small in hue change and decrease offading resistance can be obtained.

An example of the processing method with the fiber softening agentincludes a method of immersing the raw fibers of felt or felt in thewatered-down softening agent, but the processing method is not limitedto this method.

In the invention, in case that a felt in which fibers have beenprocessed with the fiber softening agent is made, the felt may be madeby the fibers processed with the fiber softening agent in advance, orthe felt after being made may be processed with the fiber softeningagent.

The tennis ball of the invention is more preferably formed into a needlefelt ball. Hereby, it is possible to obtain a tennis ball which can beused appropriately in a court (for example, a carpet court) where thefelt is prone to fluff up and therefore, a ball felt which is high indurability is preferably used.

In the manufacture of needle felt used in the above-mentioned needlefelt ball, short fibers (batt fibers) are implanted and fixed onto abase fabric by a needle-punch method, whereby the needle felt which is anon-woven fabric having a fluffing-up surface can be obtained (refer toFIG. 4).

Further, the above needle felt may have a single-layer structure or amultilayer structure. As the needle felt having the multilayerstructure, there is for example, the needle felt in which a polyesterfiber or an acryl fiber is used as a fiber, a nylon fiber or a mixedfiber of wool and nylon is used as a fiber in a lower felt layer havingthe above-mentioned structure (1) to (3), and an upper felt layer havingthe above-mentioned constitution (1) to (3) is laminated on the lowerfelt layer.

In case that the needle felt having the above multilayer structure isprocessed with the fiber softening agent, it is necessary to select amain component of the fiber softening agent so that the softeningproperty can be provided for the fibers in all the layers. However, inthe invention, it is permissible that the softening agent is not used atall, the softening agent may be used in only the felt having theaforementioned constitution (1), the softening agent may be used in onlythe felt having the aforementioned constitution (2), or the softeningagent may be used in only the felt having the aforementionedconstitution (3).

The felt of the invention in which the base fabric and the fibers arefixed together may be made by other methods than the needle punchmethod.

The tennis ball shown in FIG. 3 was made by the following procedure.

(1) A fiber blend containing a wool fiber and a nylon fiber at apredetermined ratio was formed in the shape of a sheet, and plural fiberblend sheets were layered as a raw fabric of felt fibers.

(2) A base fabric was prepared, which is formed of polyurethane fibershaving stretch property, has a mesh structure in which each mesh ishexagonal, and is stretchy in a longitudinal direction, a lateraldirection, and an oblique direction.

(3) The base fabric and the raw fabric were laminated and subjected toneedle-punch processing by a needle-punch machine in which needles arestuck into the lamination from the raw fabric side, whereby the basefabric and the short fibers were fixed together and needle felt which isa non-woven fabric having a fluffing-up surface was made.

(4) The obtained needle felt was immersed in a watered-down softeningagent, and thereafter dried. As a main component of the fiber softeningagent, a polyimide type cationic surfactant was used.

(5) The needle felt processed with the fiber softening agent was punchedout in the substantially gourd-shape.

(6) Two sheets of the above needle felt were adhered onto the peripheryof a spherical core formed of cross linked rubber with a rubberadhesive, whereby a needle felt ball was made.

When the tennis ball was made using the above-mentioned needle felt, nocreases were produced on the felt.

Further, by the needle-punch method, the following needle felt A to Cwere made. In this case, the softening agent was not used.

*Needle felt A: a felt which uses a base fabric formed of polyurethanethat is stretchy material and having a hexagonal mesh structuredeveloping stretch property, and which has the stretch property in bothof a longitudinal direction and a lateral direction (refer to FIG. 1A)

*Needle felt B: a felt which uses a base fabric composed of a wovenfabric, the woven fabric using a cotton fiber having no stretch propertyfor one of warp and woof, and a polyester fiber having no stretchproperty for the other thereof, and therefore having stretch property inneither of the longitudinal direction and the lateral direction, thefelt having stretch property in neither of the longitudinal directionand the lateral direction

*Needle felt C: a felt which uses a base fabric of which material is thesame as the material of the base fabric of the needle felt B and ofwhich thickness is larger than the thickness of the base fabric of theneedle felt B.

Regarding felt pieces obtained by punching out the needle felt A to C inthe substantially gourd-shape, a relationship between stress andelongation when each felt piece was pulled till each felt was broken wasbeen examined by a Tensilon tester. A result of the examination is shownin FIG. 2. From the result in FIG. 2, it is found that the felt usingthe stretchy base fabric is higher in stretch property than the feltusing the base fabric having no stretch property.

When the tennis balls were made using the above-mentioned needle felt Ato C punched out in the substantially gourd-shape, creases were producedon the felt B and C, but creases were not produced on the felt A.

1. A tennis bass felt, which is covered on a core of a tennis ball,comprising: a base fabric formed of stretchy material; and fibers fixedwith the base fabric.
 2. The tennis ball felt according to claim 1,wherein the felt is needle felt formed by fixing the base fabric and thefibers together by a needle punch method.
 3. The tennis ball feltaccording to claim 1, wherein, the fibers are processed with a fibersoftening agent.
 4. The tennis ball felt according to claim 3, wherein amain component of the softening agent is a polyimide type cationicsurfactant.
 5. A tennis ball comprising: a core; and a tennis ball feltincluding: a base fabric formed of stretchy material; and fibers fixedwith the base fabric, the tennis ball felt covering the core.
 6. Atennis bass felt, which is covered on a core of a tennis ball,comprising: a base fabric having a mesh structure which develops stretchproperty; and fibers fixed with the base fabric.
 7. The tennis ball feltaccording to claim 6, wherein the felt is needle felt formed by fixingthe base fabric and the fibers together by a needle punch method.
 8. Thetennis ball felt according to claim 6, wherein the fibers are processedwith a fiber softening agent.
 9. The tennis ball felt according to claim8, wherein a main component of the softening agent is a polyimide typecationic surfactant.
 10. A tennis ball comprising: a core; and a tennisball felt including: a base fabric having a mesh structure whichdevelops stretch property; and fibers fixed with the base fabric, thetennis ball felt covering the core.
 11. A tennis bass felt, which iscovered on a core of a tennis ball, comprising: a base fabric formed ofstretchy material and having a mesh structure which develops stretchproperty; and fibers fixed with the base fabric.
 12. The tennis ballfelt according to claim 11, wherein the felt is needle felt formed byfixing the base fabric and the fibers together by a needle punch method.13. The tennis ball felt according to claim 11, wherein the fibers areprocessed with a fiber softening agent.
 14. The tennis ball feltaccording to claim 13, wherein a main component of the softening agentis a polyimide type cationic surfactant.
 15. A tennis ball comprising: acore; and a tennis ball felt including: a base fabric formed of stretchymaterial and having a mesh structure which develops stretch property;and fibers fixed with the base fabric, the tennis ball felt covering thecore.